Umlauts display as question marks

Hello,
When my address text or the recipients name contains umlauts like ? and ?, they display as question marks in the shipping label when the cyrillic encoding is on. If it is off, there are more weird symbols in place of the umlauts.

For example:
J??skel?inen –> J??skel?inen or J?¤?¤skel?¤inen
Retriittity? –> Retriittity? or Retriittity??

Can anything be done about this?
Thank you.

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